Skid



SKID

2 Sheets-Shet 1 Filed March 26, 1927 i/awzder fraM/kfl" his ("1% Aug. 4,1931. A. PROCOFlEFF-SEVERSKY 1,817,901

SKID

Filed March 26, 1927 2 Sheets-Sheet 2 Patented Aug. 4, 1931 \UNITEDSTATES: PATENT OFFICE ALEXANDER PROCOFIEFF-SEVERSKY, OF NEW YORK, 1\T.Y., ASSIGNOR, BY MESNE AS- SIGNMENTS, T0 SEVERSKY AIRCRAFT CORPORATION,A CORPORATION; OF DELA- WARE SKID

Application filed March 26, 1927. Serial No. 178,533.

The present invention has been developed in connection with theproduction of an improved skid for landing gear for aircraft and such anarrangement will be described for the purpose of illustrating theprinciples of the invention but this description is illustrative merelyand is not intended as defining the limits of the invention.

' There are certain advantages in making the ground engaging skids orskis of aircraft landing gear from metal because of the facility ofmanufacture and strength obtainable but when metal skids are used in thesnow or water the adherence of freezing snow and ice to the undersurface of the skid makes serious trouble. It has been found that if thesurface of the metal is suitably lubricated the tendency of the snow andice to adhere is reduced or eliminated. The present invention provides ametal skid of improved construction having provision for lubricating theground engaging surface. This is of advantage in landing on and takingoff from snow and in other circumstances where lubrication is desired.The preferred construction aifords a rigid shell-like structure which ispreferably of stream line contour with oil carrying space within. Otherfeatures of and advantages obtained by the invention will appear fromconsideration of a selected illustrative embodiment thereof.

In the drawings forming a. part hereof Figure 1 is a top plan view of amonocoque skid or pontoon constructed in accordance with and embodyingthe principles of the invention. v

Figure 2 is a side view of the skid indicating the manner of attachmentto an aircraft.

Figures 3, 4, 5, 6 and 7 are sectional views taken respectively on thelines 33, 4-4, 5--5, 66 and 7-? indicated on Figure 2.

Figure 8 is a horizontal sectional view taken on the line 8-8 of Figure7.

Figure 9 is a central vertical sectional view taken longitudinally ofthe skid showing the arrangement of an oil reservoir.

Figure 10 is a transverse sectional view of the same. i

Figure 11 is a longitudinal sectional view showing in detail thearrangement of a reservoir at the forward end of the skid, and

Figures 12 and 13 are sectional views showing an auxiliary valve meansfor closing the outlet port.

The arrangement shown for the purpose of illustrating the inventioncomprises a monocoque skid, pontoon, or bther equivalent, forming a partof the landing gear of an airplane. The skid consists of a hollow shellof stream line contour, the shape of which is designed to give thedesired strength in a hollow shell structure. As shown, the skidcomprises an upper shell 5, formed to provide strength longitudinally ofthe skid and to present a substantially stream line contour externally,together with a base plate 6 which may be flat or corrugatedtransversely and attachment of the skid to the landing gear.

As best shown in Figures 7 and 8 upright members 10 are rigidly securedwithin the shell and adjacent the lateral edges thereof, which membersare connected by a hub member 11 arranged to fit the usual axle 12 ofthe aircraft landing gear. The shell is preferably reinforced adjacentthe points of attachment of said upright members 10 as by means of anglemembers 14 and 15. Suitable strips 16 are secured to the angle bars 14and 15 and i to the uprights 10 to make rigid the structure.

In order to hold the skid in horizontal position, suitable tie membersare connected to said skid and to the body of the aircraft or to thelanding gear thereof. In the arrangement shown eyes 18 and 19 aresuitably formed as part of the skid and to these (:"35

suitable tie members 20 and 21 are secured, these members preferablybeing yieldahlr t provided with an outlet at the bottom thereof.

This outlet is closed by a valve 27 engaging the suitable seat 28 andnormally held in closed position by a spring 29 confined between thevalve 27 and a fixed bracket 30 secured to one wall of the oil chamber.Any suitable provision may be made for moving the valve 27 to openposition to permit flow of the oil. Preferably, automatic means isprovided for moving this valve and as shown a yieldable skid member 31is riveted at its forward end to the skid as indicated at 32. The skidmember 31 is preferably formed of spring steel arranged normally to liein a position substantially out of engagement with the valve 27 butarranged to be pressed inwardly against said valve to open same duringlanding of the ski or during take off.

The spring skid member 31 may be so designed that it will guide the oilfrom the outlet 26 down along the under surface of the skid, or it maybe so arranged that the oil flows on to the ground or snow in front ofthe bearing surface of the skid. In the particular arrangement shownthis member is transversely corrugated providing grooves so that it willnot many event operate to close the outlet 26 when pressed upwardly byengagement with the ground. Ordinarily it is not necessary to providemeans for directing oil to a oint forward of the control member 31 but 0viously such means may be provided if desired. a

The oil chamber 26 is in general similar to the oil chamber 25previously described. As-

shown it comprises a casting 35 with partition walls 36 and 37 withinthe skid which serve to reinforce the skid and to form the oil chamber.The valve 38 is operated by a spring member 39 as in the case of thevalve hereinbefore described.

Inasmuch as the valves controlling the oil chamber outlets are openedautomatically by engagement of the skid with the ground it is desirableto provide manually operable means for closing said valves after landingor while the aircraft is resting above the ground. This can be done inany suitable 0r preferred manner. In the arrangement shown auxiliaryvalve members are provided which may be moved inwardly by cams.

Referring to Figures 12 and 13, in which is shown a sufficientlyillustrative arrangement auxiliary valve seat members 40 are provided inposition to be moved inwardly against the valve 38 to close the outletwhen this valve is held in its inner position. As shown the members 40are moved inwardly by slides 41 actuated by cams 42. The slides 41 andvalve members 40 are' normally held at a predetermined distance fromeach other by springs 43 on rods 44 and when the cams 42 are moveddownwardly by the rods 45, which extend above the skid for operation,the members 40 will be spring pressed against the valve 38.

Oil has been mentioned as a typicallubricant but this is merelyillustrative. As a matter of fact, soap or soap solution is in somerespects a better lubricant.

The invention may be variously embodied and various changes may be madein the embodiment described without departing from the spirit of theinvention as defined in the appended claims.

I claim:

1. A skid comprising a lubricant chamber, a valve and means forautomatically opening said valve upon engagement of the skid with theground to distribute lubricant to the ground engaging surface of theskid.

2. A skid comprising a lubricant chamber, an outlet therefor, a valvenormally closing said outlet and pressure actuated means 0 erable uponengagement of the skid with t e ground to open said valve.

3. A skid of monocoque construction com prising a lubricant chamber, anOutlet therefrom, a valve normally closing said outlet, a groundengaging skid element arranged upon pressure with the ground to opensaid valve and serving as a guide to carry lubricant from the outlettoward the surface of the skid.

4. A skid comprising a lubricant chamber having an outlet, a valvenormally closing said outlet toward the forward end of the skid,manually operated means for closing said outlet and means for directinglubricant flron said outlet to the under surface of said s n 5. A skidcomprising a lubricant chamber,

